The Act on Preventing Collisions at Sea stipulates that a vessel shall display a light provided in the Act between sunset and sunrise. Examples of the light provided in the Act, namely, a navigation light include a bow light, a side light, and a stern light. A navigation officer views the navigation light of the other vessel to determine a size and a direction of the vessel at night. Therefore, if the navigation light is turned off due to a failure or the like, the state of the vessel cannot be correctly grasped by the other vessel, which disturbs safe sea traffic. Accordingly, a control apparatus that outputs an alarm and switches the light source to a standby light source when the light source of the navigation light is turned off due to the failure, is known.
Further, although a bulb has been used as the light source of the navigation light, the bulb is replaced with an LED in recent years in order to save power, etc. Patent document 1 discloses a control apparatus that controls lighting of a navigation light using the LED.